title: Lack of an antibacterial response defect in Drosophila Toll-9 mutant.
abstract: Toll and Toll-like receptors represent families of receptors involved in mediating innate immunity response in insects and mammals. Although Drosophila proteome contains multiple Toll paralogs, Toll-1 is, so far, the only receptor to which an immune role has been attributed. In contrast, every single mammalian TLR is a key membrane receptor upstream of the vertebrate immune signaling cascades. The prevailing view is that TLR-mediated immunity is ancient. Structural analysis reveals that Drosophila Toll-9 is the most closely related to vertebrate TLRs and utilizes similar signaling components as Toll-1. This suggests that Toll-9 could be an ancestor of TLR-like receptors and could have immune function. Consistently, it has been reported that over-expression of Toll-9 in immune tissues is sufficient to induce the expression of some antimicrobial peptides in flies. These results have led to the idea that Toll-9 could be a constitutively active receptor that maintain significant levels of antimicrobial molecules and therefore provide constant basal protection against micro-organisms. To test theses hypotheses, we generated and analyzed phenotypes associated with a complete loss-of-function allele of Toll-9. Our results suggest that Toll-9 is neither required to maintain a basal anti-microbial response nor to mount an efficient immune response to bacterial infection.
authors.affiliation: Institut de Biologie du Développement de Marseille-Luminy, CNRS UMR 6216/Aix-Marseille II University, Campus de Luminy, Marseille, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Narbonne-Reveau
authors.forename: Bernard
authors.initials: B
authors.lastname: Charroux
authors.forename: Julien
authors.initials: J
authors.lastname: Royet
mesh_terms: D000375:Aging / Q000235:genetics / Q000276:immunology; D000818:Animals; D030801:Animals, Genetically Modified; D023181:Antimicrobial Cationic Peptides / Q000378:metabolism; D001419:Bacteria / Q000276:immunology*; D004330:Drosophila / Q000235:genetics* / Q000276:immunology*; D029721:Drosophila Proteins / Q000235:genetics* / Q000502:physiology; D005260:Female; D055786:Gene Knockout Techniques; D006434:Hemocytes / Q000166:cytology; D007113:Immunity, Innate / Q000235:genetics*; D008297:Male; D051193:Toll-Like Receptors / Q000235:genetics* / Q000502:physiology; D023084:alpha-Defensins / Q000378:metabolism
chemical_list: D023181:Antimicrobial Cationic Peptides; D029721:Drosophila Proteins; C560610:Toll-9 protein, Drosophila; D051193:Toll-Like Receptors; D023084:alpha-Defensins